French Toast: 
Butter, for greasing
1 loaf crusty sourdough or French bread
8 whole eggs
2 cups whole milk
1/2 cup whipping (heavy) cream
1/2 cup granulated sugar
1/2 cup brown sugar
2 tablespoons vanilla extract

Topping:
1/2 cup all-purpose flour
1/2 cup firmly packed brown sugar
1 teaspoon ground cinnamon
1/4 teaspoon salt
Freshly grated nutmeg
1 stick cold butter, cut into pieces, plus more for serving
Warm pancake syrup, for serving
1 cup fresh blueberries, for serving